COLORED ICONS

[Comercial_Maqst]

There could be an option to choose the color of the icon when it is not selected, maybe for desktop only. It would be a nice way to give it a more vivid look and even use colors to "group", identify sections.

[dbaum]

ICYMI, see Format Rules: The Essentials - AppSheet Help.

As an example, Expand/Collapse Button Groups - Google Cloud Community illustrates use of colors to distinguish button groups.

[Comercial_Maqst]

Hi, sir.

It is not I what I meant. I am speaking about the primary  icons of the app, the ones down below that represent each view. I am aware of format rules. 
Thanks anyway.

[dbaum]

Experiment with the app's footer Style property. That may be what you're seeking.